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<p>A novel Co-Ni-ZnO decorated nitrogen-doped graphene oxide (Co-Ni-ZnO/NGO) nanocomposite was synthesized via hydrothermal and co-precipitation methods followed by calcination for sensitive electrochemical nitrite detection. The synthesized nanocomposite was characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). FTIR confirmed the formation of metal-oxygen bonds, while XRD revealed a crystalline structure with an average crystallite size of 25&#xa0;nm. SEM analysis demonstrated the uniform distribution of Co-Ni-ZnO nanoparticles on NGO sheets with an average particle size of approximately 29&#xa0;nm, and EDX confirmed the presence of C, O, Co, Ni, and Zn elements. The electrochemical performance of the Co-Ni-ZnO/NGO modified glassy carbon electrode (GCE) was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The modified electrode exhibited enhanced electrocatalytic activity toward nitrite oxidation due to the synergistic interaction between the trimetal oxide nanoparticles and the conductive NGO matrix. Under optimized conditions, the sensor displayed a linear response range of 1.5–78 µM, a sensitivity of 1.945 µA µM⁻¹ cm⁻², and a low detection limit of 3.87 nM (R² = 0.9918). In addition, the sensor demonstrated excellent selectivity, reproducibility, and stability. Recovery studies in food and environmental samples confirmed its practical applicability. These results suggest that the Co-Ni-ZnO/NGO nanocomposite is a promising electrocatalytic material for reliable nitrite detection in environmental monitoring and food safety applications.</p> Graphical abstract <p><b>Scheme 1.&#xa0;</b>Schematic illustration of the synthesis of the Co-Ni-ZnO/Nitrogen-Doped Graphene Oxide (Co-Ni-ZnO/NGO) nanocomposite and its proposed electrocatalytic mechanism for electrochemical nitrite detection</p> <p></p>

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Co-Ni-ZnO decorated nitrogen-doped graphene oxide nanocomposite for sensitive electrochemical nitrite detection

  • 期刊论文

  • 发表日期：

    2026年6月20日

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  • Jayashree M,
  • Manjunatha C. V,
  • Y. Venkataramanappa

摘要

A novel Co-Ni-ZnO decorated nitrogen-doped graphene oxide (Co-Ni-ZnO/NGO) nanocomposite was synthesized via hydrothermal and co-precipitation methods followed by calcination for sensitive electrochemical nitrite detection. The synthesized nanocomposite was characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). FTIR confirmed the formation of metal-oxygen bonds, while XRD revealed a crystalline structure with an average crystallite size of 25 nm. SEM analysis demonstrated the uniform distribution of Co-Ni-ZnO nanoparticles on NGO sheets with an average particle size of approximately 29 nm, and EDX confirmed the presence of C, O, Co, Ni, and Zn elements. The electrochemical performance of the Co-Ni-ZnO/NGO modified glassy carbon electrode (GCE) was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The modified electrode exhibited enhanced electrocatalytic activity toward nitrite oxidation due to the synergistic interaction between the trimetal oxide nanoparticles and the conductive NGO matrix. Under optimized conditions, the sensor displayed a linear response range of 1.5–78 µM, a sensitivity of 1.945 µA µM⁻¹ cm⁻², and a low detection limit of 3.87 nM (R² = 0.9918). In addition, the sensor demonstrated excellent selectivity, reproducibility, and stability. Recovery studies in food and environmental samples confirmed its practical applicability. These results suggest that the Co-Ni-ZnO/NGO nanocomposite is a promising electrocatalytic material for reliable nitrite detection in environmental monitoring and food safety applications.

Graphical abstract

Scheme 1. Schematic illustration of the synthesis of the Co-Ni-ZnO/Nitrogen-Doped Graphene Oxide (Co-Ni-ZnO/NGO) nanocomposite and its proposed electrocatalytic mechanism for electrochemical nitrite detection